These results support the role of aberrant chromatin accessibility and consequent oncogenic <i>MYC</i> enhancer activation in NOTCH1-induced T-ALL.<i>This article is highlighted in the In This Issue feature, p. 1631</i>.
Two T-lymphoblastic leukemia (T-ALL) cell lines and two acute myeloblastic leukemia (AML) cell lines were transfected with siRNAs targeting NOTCH1 and NOTCH2.
Interestingly, gain-of-function mutations or cryptic transcription initiation of the Notch1 gene have been frequently found in both human and mouse T-ALL.
To further investigate the molecular mechanisms underlying proliferation suppression and apoptosis and explore effective downstream target genes, we used RNA interference (RNAi) technology to down-regulate the expression of Notch-1 in GSIs-resistant T-ALL cell lines.
Here we have investigated the prognostic impact of mutations in the NOTCH1 pathway, in particular, the NOTCH1 and FBXW7 genes, in a large cohort of adult patients with T-lymphoblastic leukemia (n=126).
Using parallel studies in T cell progenitors and established T-ALL lines we have demonstrated that the NFkappaB signaling pathway is targeted and induced by Notch1 activation.
These results show that the CUTLL1 cell line has a strong dependence on NOTCH1 signaling for proliferation and survival and supports that T-ALL patients whose tumors harbor t(7;9) should be included in clinical trials testing the therapeutic efficacy NOTCH1 inhibition with GSIs.